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Sandblasting after hardening, blackwashing


Chimaera

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Hi! I'm new to this forum, along with forging in general. I've made a few leaves and trinkets, but I don't get the same dopamine hit as from making a knife. I'm looking to blackwash my next blade, and think a sandblasted finish would work nicely. I have access to an industrial sandblaster that is used for aluminum, but I can't find anything about sandblasting steel, especially after the heat treat. Any help in that regard would be appreciated. Also, for a blackwash, what should I use for the patina if I'd like a solid black finish (forging rebar for now)? Preferably a household chemical. I've heard instant coffee gives a very dark etch? Thank you.

 

Chimaera

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You should use the chemical that works best for the alloy YOU are using. Here in the USA generally sourced Rebar is not a good alloy for blades, auto coil springs can be sourced cheaper and is a decent alloy. (Often 5160)  You may want to look up "hot bluing" as is used on firearms---it works on blades as well.

  BTW if you stop by COAS  on Main street, they had a couple of copies of the TM on blackening steel.  I didn't pick one up as I already have a copy of: 

"Firearm Blueing and Browning", R. H. Angier;   Stackpole Books, 1936 - Sports & Recreation - 151 pages "A comprehensive manual with over 230 formulas for chemical and heat colouring of gun metals and for other processes".   (Like most older books on chemical processes it assumes you already know the safety precautions and won't kill yourself being stupid!)

The swordmaker I worked a year under used to bead blast metals for twisted wire grips, less aggressive than sandblasting.

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Thank you for the advice. I've been looking into getting some coil springs, just haven't gotten hold of any yet, and thought rebar could be good practice. I will look into getting something from the library. So, your consensus on the sand is that it might be a little too aggressive?

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Theyre actually shiny as in the first picture.

The bottom picture was actually my first taken. I used the flash, and it didn't pick up the lettering well. But it did show a contrast in the darkness of the blueing. Without the flash, the black looks more brownish in the house lights.

In that shot, I hadn't removed the black vinyl letters yet.

I have a vinyl plotter, and I used it to cut out the stencils for my friends name, as a mask for the blueing. The blade was hand sanded up to 2500 grit paper, then buffed on a polishing wheel with rouge before cleaning and blueing.

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8 hours ago, Chimaera said:

Ah! Makes sense. So, the whole thing (except the letters) is black? Sorry for all my questions, I'm just trying to figure out what I'm doing.

Yes, all black but the letters.

Nope, no worries on questions. Asking and doing are how you learn things!

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Ok, I'll look at getting some of that. Right now I just have a piece of scrap that I'm dropping in coffee, vinegar, etc to see if it does anything XD. To the best of your knowledge, will that cold bluing work on 5160? I'll probably be getting some of that, and maybe some O1 or W1.

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Blueing works on high carbon steel to my knowledge. The knife in that picture was made from a piece of leaf spring from an army vehicle. I found it in a scrap metal bin in a motorpool on ft hood texas in 2006-2007.

I've held onto it since then to make myself a knife.

One of my best friends, my truck mechanic while deployed to iraq- gave me my anvil. I promised him the first good blade that came off it... so he got it made from that piece of spring.

In general terms leaf springs are 5160 or close. So, yup... it should work. I blued that one completely cold. Applied a coat, let it set, rinsed it in water and coated again. I believe I did it three times if I remember just to get a decent coating.

My research and the advice from a machinist friend who recommended the birchwood- shows that you get a better reaction and more even coating when done with warmed metal. Not hot, like forging temps... but 180-200 degrees Fahrenheit or so?

He uses it to blue the knobs and hardware on his work- like the hardware on my belt sander he built in the picture. The knurled handle, and adjustment knob are done with the birchwood.

20200614_194335.jpg

Where are you in the world chimaera?

If you go to your profile block, you can update your location and anyone that clicks on your name can see it. That lets us have... a better idea of advice to give on where you can find things.

For example- a great etching solution is ferric chloride. Depending on where you are... i got mine online thru amazon, 945ml bottle. I'm in the US in ohio, and had it delivered right to my door- relatively decently priced. It's then diluted down with water, dependant on your desired etch strength, and lasts for multiple uses. It's around $30.

 

20201106_010941.jpg

Sorry for the huge picture! I tried to resize it, but the file size drops, still humongous.

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Thank you for your service. Sounds like you got a good truck mechanic! I've actually got somethin' of a similar deal. My great uncle gave me my anvil, (RR, but it still works) when I was just a little kid. Now that I've started forging, I'm trying to make him a good knife.

Hey, would you look at that. I'm OH too. Cincy. I figured if I wanted to do some good etching I'd have to bite the bullet and get some FeCl3. I'm just on a fairly tight budget (railroad anvil, homemade forge, rebar) and wasn't sure how much use one could get out of a bottle of Ferric Chloride. I'll probably check the Lowe's that's 1/4 mile away. What would you suggest for a dark, even protective finish? Cold bluing or FeCl3? Thank you.

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I bought the cheapest black tea I could find and boiled a lot of it for an hour or so and immersed my blade in the hot solution and left it over night.  When I checked it in the morning it looked like my blade was "furry" and I thought the experiment had failed; but when I went to wash it under the faucet, the fur stripped off leaving purple black  colour---this was a pattern welded blade; I was experimenting with possible etchants mentioned in "The Sword in Anglo-Saxon England.)  Further research showed the use of tannin as a rust resistant surface prep in Iron working books.

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Ah, come on! There's good bagged tea! Most of it is loose, but maybe they got sacrificed because they're bagged! Tried this a while ago, found some of my new favorite teas (cream earl gray, calming blend). https://www.onsullivan.com/products/tea-tour

Touche... I've had some visitors who were all too happy to take my best... <_<

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We had an exchange student from Sri Lanka spend a year with us when I was in High School; we still correspond, anyway he brought a tea sampler of the various teas available there, (and was *quite* against bagged tea!)  Turns out I like some of the heavier teas commonly drunk in the middle east.  (And with way too much milk and sweetner---a friend in our church from the UK tells me that I drink "Builder's Tea".  I used to brew up 64 ounces of it every day and carry it across the border to drink at my job in Mexico.)

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2 hours ago, Jealdi said:

Ooh.. Teas... I love tea. Thanks for that site Chimaera!

They have a few different tours (looks like they're sold out on all of them... guess people like it, and for good reason!). I got the flavor in the mix for Christmas, got 3 1oz bags a month. Mostly black, some green, a little herbal, rooibos, and white. Good stuff. After my 6 months, same friends got me 1lb of the cream earl gray. That stuff is freakin' delicious, especially with a drop of heavy cream and a tiny bit of sugar.

2 hours ago, ThomasPowers said:

We had an exchange student from Sri Lanka spend a year with us when I was in High School; we still correspond

My dad goes over to Taiwan every so often for work, and he often has coworkers hand him a lb of tea for me... A little too floral for me, but a kind gesture and still yummy. I also "ruin" it with sugar and cream... I just like it more that way...

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